As the Warriors and Cavaliers get extended time off before they have to play again, how does history show the rest will impact their games?

In today’s NBA, where we can track player fatigue like never before and players’ movement on the court down to the inch, it is no surprise that rest became a major talking point this season. While sitting stars during primetime games became a hot-button issue for the league office, the playoffs are centered around a less divisive form of rest.

After Golden State finished off their four-game sweep of Utah last Sunday, they joined Cleveland as the first pair of teams to both start 8-0 in the same postseason. As reward for their early dominance, both have had at least five days off between the first and second round, and between the second and upcoming third round.

While teams fight as hard as they can to get that extended time off, there are some who believe that the rust it creates can be just as detrimental as the rest is beneficial. Do these teams really benefit from time off? Or do they come out flat and put themselves in an early hole the next series?

In order to try to answer these questions, I tracked the stats for every team that had extended rest between series over the past decade. This includes every team that finished their series in two or three fewer games than did their upcoming opponent. So, while Golden State and Cleveland finished their series in a tidy four games, their opponents in the Conference Finals will have won their series in six or seven.

Including this year’s Warriors and Cavaliers, there have been 23 teams since 2007 that fit that criteria (the 2013 Spurs and 2016 Cavs did it twice and therefore each count as two separate teams). While this isn’t a huge sample, there are enough teams to paint a pretty good picture.

For each of these teams, I tracked their plus/minus, effective FG% (eFG%), and turnover percentage (TO%) over the regular season, Game 1 of their next series, and their average over the entirety of the series. Plus/minus gives us a good look into margin of victory, while eFG% and TO% were the best stats in my mind to measure rust. A team suffering from time off would likely miss shots they would normally make and might turn the ball over due to lack of flow between teammates.

Next to the regular season, Game 1, and series stats in each table, there is a percent difference between game one and the regular season average, and the series average and the regular season average.

Fifteen out of the 23 teams who fit the criteria won the first game of their next series. Considering the level of talent it takes to win a playoff series in four or five games, a 65% win percentage isn’t surprising. Even the margin of victory drop-off of 2.6 pts/gm is well within the expected range with the increased competition in the playoffs.

What is notable is that the number of teams that won their series jumps to 19. In addition to all 15 Game 1 winners, four of the teams that dropped their first game managed to come back and win their series. Almost across the board, the margin of victory improved as the series progressed and the average +/- jumped over 15% from the first game of the series to the end of it.

Plus/minus is a great way to measure team overall success, but it isn’t a great tool in measuring exactly how well they played in those games. EFG% is very similar to traditional FG%, but recognizes that 3-point shots are worth 50% more than 2-point shots and weighs them accordingly.

Similarly to +/-, eFG% shows that teams struggle in Game 1 more than usual after the long break. While a couple of teams like the 2010 Hawks and 2013 Heat skew the data a little bit, over half the teams shot worse in Game 1 than they did in the regular season.

To try to put that 3% drop in perspective, the 52.4% average for the regular season would have been 10th in the league this season or roughly equivalent to the San Antonio Spurs. If you compare that to the 50.7% average for Game 1, they would have dropped to 17th and been equivalent to the Brooklyn Nets. While the decrease seems negligible, it is far from insignificant.

Finally, TO% measures how often a team turns the ball over per 100 possessions. Unlike the previous two stats, the lower the number the better and so a negative “% change” is what teams are looking for in the playoffs.

Interestingly, unlike the previous two stats where teams improved over the course of the series, the trend shows that teams actually turned the ball over more as the series progressed. As expected, this elite level of team did a very good job at avoiding turnovers regardless of the point in the series, but they did drop from what would have been third best in the league in Game 1, to what would have been 10th over the entire series.

The most plausible explanation I can derive from this is that as the series progresses, regardless of rest, your opposition begins to adapt to what you are trying to do offensively. The offense you were running in game one becomes harder by the time games four and five roll around, which may very well account for the extra one or two turnovers per game.

Ultimately though, what does this data tell us? Everyone can draw their own conclusions, but to me, this shows both rest and rust have their impacts after time off. The lower margin of victory and eFG% in Game 1 indicates that rust has its impacts over the first 48 minutes of a series; but the improvement as the series goes on indicates that rest only helps more and more the longer the series goes.

The fact that 83% of teams with this substantial amount of rest ended up winning their series is a very strong indication that it does have its benefits. However, the subjectivity of the data leaves room for interpretation as to how much of an impact is is making. What the recent trends and that 83% do tell us, is that everything certainly appears to be lining up for Warriors-Cavs part III.